Well, I can't send a debug. I finished that game and went on to another already.
The Iconian fleet that had my fighter was about 1/4 of the way across the galaxy (huge galaxy setting) when it first started to autofocus to that location. I can't honestly remember if I was attacking ships in orbit at that moment, but I don't think I was.
I had just taken two planets from them.... and now that I think of it, I'm pretty sure I was launching fighters from one of their former worlds when it started happening. Can't remember if I bought any fighters on that planet. I'm pretty sure I wouldn't have, because it had a precursor mine and could pop out one of those fighters every week.
We were both well away from any planets when that battle happened.